Click on the Adjustments Panel and add the Curves Layer there. Look at the "Properties" Panel to see the Curve. At the upper right corner is a tiny, nearly invisible triangle; click on that to bring up the Curves Display Options, where you will see the two icons for the two types of grids.

In a few minutes I'll make some screen shots for you, but you should be able to figure it out from this brief description.

Station Two - Just out of curiosity, where did you come across my modified version of the PhotoDisc Test Image? It's weird how you can recognize even from just a few partial pixels both the great Guy Clark and U. Utah Phillips.